1. Technical Field
The present disclosure relates to automated booklet makers, in which sheets forming a booklet are folded by passing through a pair of crease rollers.
2. Brief Discussion of Related Art
Booklet makers are well-known devices for forming folded booklets which are stapled along the crease thereof. It is becoming common to include booklet makers in conjunction with office-range printers. The word “printer” as used herein encompasses any apparatus, such as a copier, digital copier, bookmaking machine, facsimile machine, multifunction machine, etc. which performs a print outputting function for any purpose. In basic form, a booklet maker includes a slot for accumulating processed sheets, as would be produced by a printer. The accumulated sheets, forming the pages of a booklet, are positioned within the stack so that a stapler mechanism and complementary anvil can staple the stack precisely along the intended crease line. The creased and stapled sheet sets are then pushed, by a blade, completely through crease rollers, to form the final main fold in the finished booklet. The finished booklets are then accumulated in a tray downstream of the crease rollers.
Crease rollers of a booklet maker are typically urged together under spring tension and roll against each other prior to the entry of the booklet. As the booklet enters the nip, the rollers are separated. The tension is then transferred to the booklet and helps form the booklet crease. In the process of forming a booklet, the friction between the outer sheet, which physically contacts the crease rollers, and the underlying sheet helps to stabilize the outer sheet as enters the crease rollers and is folded and creased. This inter-sheet friction is influenced by such factors as the surface roughness of the sheets and the print material used to create the image on the sheets. Due to variations in surface roughness of sheets and the print material, the friction between the outer sheet and the underlying sheet may not be sufficient. Therefore, the top sheet may be torn or otherwise damaged as it passes through the crease rollers. Such tear off damage typically leads to a jam which requires clearing by an operator and significantly slows the booklet making process.
Accordingly, it would be desirable to provide a booklet maker which reliably provides a satisfactory crease while maintaining the integrity and quality of the booklet.